Muffler with multiple circumferential flow chambers



Aug. 15, 1967 w, J. ARBEITER 3,335,814

MUFFLER WITH MULTIPLE CIRQUMFERENTIAL FLOW CHAMBERS Filed Sept. '7, 1965 INVENTOR. N/LlJAM J'- ARBE/f'fl ATI'OR NEYS United States Patent 3,335,814 MUFFLER WITH MULTIPLE (IIRCUMFERENTIAL FLOW CHAMBERS William 3. Arbeiter, Kansas City, Mo., assignor to Service Products Company, Kansas City, Mo., a corporation of Missouri Filed Sept. 7, 1965, Ser. No. 485,434 3 Claims. (Cl. 18158) ABSTRACT OF THE DISCLOSURE This invention is in an exhaust muffler for silencing the exhaust of gases from small internal combustion engines with an absence of back pressure. The muffler structure includes a housing with an elongate central chamber with circular flow passages extending around same exteriorly of the chamber with communication between the passageways and the central chamber through narrow circumferential slots. The exhaust gas from an engine is discharged through a tangential connection with one circular passageway whereby the gases flow therearound with some of the gases moving through an opening to the second circular passageway for movement therearound with gases from both passageways discharging through the slots into the central chamber which has openings at one end thereof for escape of the gases therefrom.

The principal objects of the present invention are: to provide an exhaust mufller which is highly eflicient in silencing exhaust noises of small internal combustion engines; to provide such a device which does not produce substantial back pressure and thus does not materially decrease engine efficiency; to provide such a device which is relatively small in size and simple in construction; and to provide such a device which is rugged and durable in use.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings wherein are set forth by way of illustration and example certain embodiments of this invention.

FIG. 1 is a front elevational view showing a typical gasoline engine driven power lawn mower with an exhaust muflier embodying this invention attached thereto.

FIG. 2 is a perspective view of the exhaust rnuffler with a portion broken away showing interior parts thereof and exhaust flow therethrough. I

FIG. 3 is a cross-sectional view through the mufller taken on the line 33, FIG. 4, particularly showing a flow passageway extending directly between adjacent toroidal passageways within the device.

FIG. 4 is a cross-sectional View through the muffler taken on the line 44, FIG. 3, further showing the flow passageway between toroidal passageways.

Referring to the drawings in more detail:

The reference numeral 1 generally indicates an exhaust mufiier or silencer embodying this invention. The muflier 1 comprises a housing 2 including first and second generally circular end sections designated 3 and 4 and an intermediate core or section 5 located therebetween. The sections 3, 4 and 5 are preferably fabricated by casting from any suitable metal which has the requisite casting, corrosion and strength characteristics and, in the illustrated example, include external cooling fins 5'.

The first end section 3 has opposed outer and inner faces 6 and 7 and a central cylindrical inner wall 8 forming an axially extending cylindrical chamber 9. A cap portion 10 closes the chamber 9 at the outer face 6. The wall 8 terminates in a circular axially directed lip 11 defining an open end 12 of the chamber 9 opposed to the 3,335,814 Patented Aug. 15, 1967 cap portion 10. The first end section 3 has a circular outer wall 13 extending radially outwardly of the inner wall 8 and forming a circular trough or depression 14 of semicircular cross-section extending into the inner face 7 and surrounding the cylindrical chamber 9. An outer radial flange 15 extends radially outwardly from the outer wall 13 for a purpose noted hereinafter. A wall portion 16 on the first end section 3 forms a tangential depressed throat portion 17 communicating at one end 18 thereof with the depression 14- and having at the other end 19 thereof an internal half thread 20.

The intermediate core or section 5 has opposed first and second faces 21 and 22 and a central inner cylindrical wall 23 forming an axially extending cylindrical chamber 24 therethrough. The wall 23 terminates at opposite ends thereof in opposed circular axially directed lips 25 and 26 defining opposed open ends of the chamber 24. The intermediate section 5 includes an outer wall 27 extending radially outwardly of the inner wall 23 and forming opposed or back-to-back separated first and second circular troughs or depressions 28 and 29 of semicircular crosssection in the respective faces 21 and 22 and surrounding the inner wall 23. An outer radial rim or flange 30 extends outwardly from the outer wall 27 and forms opposed axially directed mounting surfaces 31 and 32 positioned radially outwardly of the depressions 28' and 29. A wall portion 33 (FIG. 3) on the intermediate section 5 forms a tangential depressed throat portion 34 communicating at one end 35 thereof with the depression 28 and has at the other end 36 thereof an internal half thread 37.

A generally circular flow passageway 38 is positioned diagonally in the wall 27 and forms a branch passageway communication directly between the intermediate section depressions 28 and 29. The angle of the passageway 38 induces partial deflection of moving exhaust gases from the depression 28 to the depression 29 without changing the direction of rotation as noted hereinafter.

The second end section 4 has opposed inner and outer faces 39 and 4t and a central cylindrical inner wall 41 forming an axially extending cylindrical chamber 42. A cap portion 43 covers the chamber 42 at the outer face 40 and has perforations 44 therethrough permitting the axial exhaust of gases from the chamber 42. The cylindrical wall 41 terminates in a circular axially directed lip 45 defining an open end of the chamber 42 opposed to the perforated cap portion 43 and communicating with the chamber 24- which communicates with the chamber 9.

The end section 4 has a circular outer wall 46 extending radially outwardly of the inner wall 41 and forming a circular trough or depression 47 of semicircular crosssection in the section inner face 39 and surrounding the chamber 42. An outer radial flange 48 is formed on the outer wall 46.

The flanges 15 and 48 on the respective end sections 3 and 4 are respectively engaged with the intermediate section mounting surfaces 31 and 32 and maintained thereagainst by means of suitable screws 48' threaded into the rim or flange 30. The first and second end sections 3 and 4 cover the intermediate section faces 21 and 22. The intermediate section chamber lips 25 and 26 are respectively aligned with and spaced axially away fromv 3 tangentially at one end thereof with the first toroidal passageway 51. The half threads 20 and 37 at the other or outer end of the passageway 53 cooperates to form a complete circular internal thread 54 for mounting the muffler, for example, by means of an adapter 55 having opposed nipples with external threads which respectively engage the internal thread 54 and a suitable internal thread on the exhaust pipe 56 or block of the internal combustion engine 57.

In use, the exhaust gases are directed into the throat or passageway 53 as indicated by the arrows 58 (FIG. 2). The gases immediately tangentially enter the toroidal passageway 51 where they are forced into a circular path. A portion of the gases passing into the passageway 51 move radially inwardly through the first slot 49 into the elongated cylindrical chamber area formed by the combination of chambers 9, 24 and 42. A substantial portion of the gases entering the toroidal passageway 52 do not move through the slot 49, but rather move or branch through the flow passageway 38 into the toroidal passageway 52. When moving through the flow passageway 38, the direction of flow is not altered and the gases continue moving circularly in the passageway 52 in the same direction as in the passageway 51. The gases subsequently move from the toroidal passageway 52 through the slot 50 into the central chamber area where it joins with the gases entering from the first slot 49. All gases entering the central chamber area must come either from the slot 49 or 50. The mixed gases, now greatly reduced in turbulence and hence noise making ability, exit through the perforations 44 to the atmosphere as indicated by the arrows 59.

The above-described configuration has been found to constitute a simple, rugged device which is surprisingly effective in reducing the exhaust noise level without substantially increasing the exhaust gas back pressure.

It is to be understood that although one form of this invention has been illustrated and described, it is not to be limited thereto except insofar as such limitations are included in the claims.

What is claimed and desired to secure by Letters Patent 1s:

1. An exhaust muffler comprising:

(a) a housing having an elongated central chamber closed at one end and having means at the other end thereof for exhausting gases,

(b) said housing having first and second axially separated passageways extending circumferentially of said central chamber and spaced therefrom, first and second axially spaced circumferential slots respectively communicating between said central chamber and said passageways, said second slot being between the first slot and said other end of the housing,

(c) said housing having tangential throat means communicating with said first passageway for discharging exhaust gases thereinto, and

(d) means forming a fiow passageway communicating directly between said first and second passageways dividing gas flow from said first passageway through said first slot into said central chamber and through said flow passageway into said second passageway, the gases in said second passageway discharging through said second slot into said central chamber to mix with gases from the first slot moving toward the exhaust means, said gases in said central chamber exhausting through said exhausting means.

2. The exhaust mufiler as set forth in claim 1 wherein:

(a) said first and second passageways are circular and said flow passageway extends diagonally between said circular passageways whereby the gases directed into said second circular passageway move in the same circumferential direction as in said first circular passageway.

3. An exhaust mufiier comprising:

(a) a housing including first and second generally circular end sections and an intermediate section,

(b) said first end'section having opposed outer and inner faces and a central cylindrical inner wall forming an axially extending cylindrical chamber, a cap portion closing said first end section chamber at staid first end section outer face, said first end section cylindrical wall terminating in a circular axially directed lip defining an open end of said last named chamber opposed to said cap portion,

(c) said first end section having a circular outer wall extending radially outwardly of said inner wall and forming a circular depression in said first end section inner face and surrounding said first end section cylindrical chamber, an outer radial flange on said first end section outer wall,

(d) a wall portion on said first end section forming a tangential depressed throat portion communicating at one end thereof with said first end section depression and having an intake portion at the other end thereof,

(c) said intermediate section having opposed first and second faces and a central inner cylindrical wall forming an axially extending cylindrical chamber therethrough, said last named wall terminating at opposite ends thereof in opposed circular axially directed lips defining opposed open ends of said last named chamber, said intermediate section having an outer wall extending radially outwardly of said intermediate section inner wall and forming opposed first and second circular depressions surrounding said intermediate section inner wall in said first and second intermediate section faces, an outer radial flange on said intermediate section outer wall and forming opposed axially directed mounting surfaces positioned radially outwardly of said intermediate end section depressions, a wall portion on said intermediate section forming a tangential depressed throat portion communicating at one end thereof with said intermediate section first depression and having an intake portion at the other end thereof, and

(f) a flow passageway formed in said intermediate section outer wall and communicating directly between said intermediate section first and second depressions,

(g) said second end section having opposed inner and outer faces and a central cylindrical inner wall forming an axially extending cylindrical chamber, means forming an exhaust opening into said last named chamber at said second end section outer face, said second end section cylindrical wall terminating in a circular axially directed lip defining an open end of said last named chamber opposed to said exhaust opening,

(b) said second end section having a circular outer wall extending radially outwardly of said inner wall and forming a circular depression in said second end section inner face and surrounding said second end section cylindrical chamber, an outer radial flange on said second end section outer wall,

(i) said first and second end section flanges being respectively engaged with said intermediate section mounting surfaces whereupon said first and second end sections cover said intermediate section faces, said intermediate section chamber lips being respectively aligned with and spaced axially from said first and second end section lips forming radially open first and second circular slots therebetween, said first and second end section depressions respectively forming with said intermediate section depressions first and second toroidal passageways respectively surrounding and communicating radially with said first and second slots, said throat portions on said first end section intermediate section being aligned forming a throat communicating with said first toroidal passageway, said intake portions cooperating to form a mouth for directing exhaust gases into said mufiier.

(References on following page) 5 6 References Cited 2,554,032 5/1951 Johnston 181-58 UNITED STATES PATENTS 3,168,936 2/1965 Gordon 181-40 X FOREIGN PATENTS /1910 l 5 23,318 1904 Great Britain. Z3 g g 117,203 7/1918 Great Britain.

B. Primary Examiner. 5/ 1941 McCurdy. ROBERT S. WARD, Examiner. 

1. AN EXHAUST MUFFLER COMPRISING: (A) A HOUSING HAVING AN ELONGATED CENTRAL CHAMBER CLOSED AT ONE END AND HAVING MEANS AT THE OTHER END THEREOF FOR EXHAUSTING GASES, (B) SAID HOUSING HAVING FIRST AND SECOND AXIALLY SEPARATED PASSAGEWAYS EXTENDING CIRCUMFERENTIALLY OF SAID CENTRAL CHAMBER AND SPACED THEREFROM, FIRST AND SECOND AXIALLY SPACED CIRCUMFERENTIAL SLOTS RESPECTIVELY COMMUNICATING BETWEEN SAID CENTRAL CHAMBER AND SAID PASSAGEWAYS, SAID SECOND SLOT BEING BETWEEN THE FIRST SLOT AND SAID OTHER END OF THE HOUSING, (C) SAID HOUSING HAVING TANGENTIAL THROAT MEANS COMMUNICATING WITH SAID FIRST PASSAGEWAY FOR DISCHARGING EXHAUST GASES THEREINTO, AND (D) MEANS FORMING A FLOW PASSAGEWAY COMMUNICATING DIRECTLY BETWEEN SAID FIRST AND SECOND PASSAGEWAYS DIVIDING GAS FLOW FROM SAID FIRST PASSAGEWAY THROUGH SAID FIRST SLOT INTO SAID CENTRAL CHAMBER AND THROUGH SAID FLOW PASSAGEWAY INTO SAID SECOND PASSAGEWAY, THE GASES IN SAID SECOND PASSAGEWAY DISCHARGING THROUGH SAID SECOND SLOT INTO SAID CENTRAL CHAMBER TO MIX WITH GASES FROM THE FIRST SLOT MOVING TOWARD THE EXHAUST MEANS, SAID GASES IN SAID CENTRAL CHAMBER EXHAUSTING THROUGH SAID EXHAUSTING MEANS. 